Halloween in Venice
by Takara Phoenix
Summary: Sequel to "The High Warlock of Venice" - Nico, High Warlock of Venice, is throwing a grand Halloween mask ball. His Shadowhunter boyfriend Percy of course has to invite their friends from New York - Jace, Alec and Magnus. Only that Percy has a bit of an ulterior motive to inviting them over. Nico/Percy & Magnus/Alec/Jace slash


Malace || Shadowhunters || Nicercy || Halloween in Venice || Nicercy || Shadowhunters || Malace

Title: Halloween in Venice – Venetian Masks

Shadowhunters: Shadowhunters: The Mortal Instruments | Percy Jackson and the Olympians

Disclaimer: All rights concerning PJatO reserved to Rick Riordan for he created the awesomeness that is Nico di Angelo. Aside from the Gods, they belong to the old Greeks. All rights to the Shadowhunters show reserved to Ed Decter, the books the show is based off and its characters belong to Cassandra Clare. This fanfiction and its OCs on the other hand are entirely mine. No money is made with this, though reviews are more than welcomed.

Warnings: shounen-ai, polyamory (threesome), fluff, costumes, teasing, shoujo-ai

Main Pairings: Magnus/Alec/Jace & Nico/Percy

Side Pairings: Lydia/Isabelle, Bianca/Annabeth

Percy Jackson Characters: Perseus Jackson, Nico di Angelo, Bianca di Angelo, Annabeth Chase

Shadowhunters Characters: Jonathan Christopher 'Jace' Wayland, Magnus Bane, Alexander Gideon 'Alec' Lightwood, Lydia Branwell

Summary: The High Warlock of Venice is holding a grand Halloween ball. Percy, of course, _has_ to invite his friend from New York. And Jace is more than happy to drag his boyfriends along.

 **Halloween in Venice**

 _Venetian Masks_

"I know people accuse me of having taken in too many cats to keep track of, but I actually _am_ capable of telling them apart and knowing which ones belong here and which ones don't. And I very distinctively remember that _this one_ isn't one of mine", drawled Magnus as he walked over to the couch and grasped the golden tag on the blue collar. "Ah, see. I knew it. Not mine."

"Ha. Ha. Ha. You're so funny, Bane", huffed Percy and pulled back from the warlock.

His fingers closed around the silver tag on his collar as he glared at Magnus pointedly. Magnus smirked down at the Shadowhunter before walking around the couch to sit down next to his own Shadowhunter. Jace smiled and leaned in to kiss Magnus, Magnus' hand finding the red collar around Jace's neck to play with the golden tag. The collar was still relatively new, but Jace had really latched onto it. He loved his collar and blatantly refused to remove it, though he did glamour it when leaving the loft. But it helped him feel grounded and especially with his track-record of getting abducted and tortured and losing his name and home, it felt good to know where he belonged. Magnus and Alec had gladly indulged their little puppy.

"You know I'm just joking around, Perseus", assured Magnus gently as he got more comfortable on the couch and used his magic to lift Jace up and place him on his lap. "You are always welcomed here, after all it's thanks to you that Alexander and I get to call this precious puppy ours."

Percy had a broad, pleased grin on his lips as he watched Magnus and Jace. Jace still blushed at those semi-public displays of affection because he still sometimes had problems grasping that Magnus and Alec were his boyfriends now. With the BDSM part of their relationship, he had – oddly enough – less troubles adjusting to than with the romantic and intimate parts.

"That is _so_ cute", grinned Percy. "You know, the nerds went to the Institute. Annabeth was more than interested in reading Valentine's journals. I'm creeped the fuck out – no offense, Jace, but what that not-father of yours did and that he documented it... urgh."

"Tell me about it", drawled Jace pointedly, a sour look on his face.

He snuggled up more to Magnus on instinct, while the warlock tightened his arms around Jace. A lot had happened since the High Warlock of Venice had visited them, since Percy Jackson and Annabeth Chase had been sent to the New York Institute as backup on the hunt for Valentine. The war was over. Valentine was dead, the real Jonathan Morgenstern was dead, Jace was now a Herondale, Alec was the head of the Institute and Magnus was very happily living with both his boyfriends. Sometimes, Magnus was pretty sure that their relationship was the only thing that had made Magnus, Alec and Jace survive this war. Well, the part aside where Jace had died and come back thanks to the wish to an Angel. Magnus tightened his grip on his blonde some more.

"You're gonna crush Jace if you hug him any tighter, Bane", noted Percy amused.

"I can turn you into an actual cat. It would be nice and calm", countered Magnus dryly.

"I don't mind being squished by my possessive boyfriends", chuckled Jace pleased.

"Can we move on to the part where you explain to me why exactly you're in my loft, Perseus?", inquired Magnus casually. "I feel like there has to be a _reason_ you and Annabeth just popped up."

"Ye—eah. Annabeth is in desperate need of Izzy's help", hummed Percy casually.

"You forgot to mention _that_ earlier", grunted Jace with a glare, kicking Percy.

"Ouch. Why do dogs always attack poor, helpless kittens?", gasped Percy offended. "You need to get a leash for that one, Magnus. He's _dangerous_. Anyway. Annabeth needs the help of your gorgeous seductress of a sister because Annie is _desperate_ to get laid."

"Ew. To literally everything in that last sentence", grunted Jace, kicking Percy again.

This time, Percy managed to block it because he saw it coming. "What? Izzy is hot and she really knows how to use her sexuality to her advantage. Ahaha. You and Alec make the funniest faces when I say stuff like that. That alone is all the reason I need to mention it, really."

"Does she just generally want to get laid, or is there more to this story?", asked Magnus casually.

"Oh. Yeah. Annie's trying to get into my future sister-in-law's pants", replied Percy with a grin.

"...Which one?", asked Jace suspiciously, squinting a little. "I thought Hazel was dating the Alpha of the New Orleans pack and that weird little warlock with the fire-magic obsession."

"Oh my gosh, you haven't even _met_ Bianca yet!", gasped Percy excitedly, grin growing. "You're going to love this! I swear, the way Annie is mooning over her is adorable!"

"...Bianca?", echoed Magnus surprised. "I thought she moved to Las Vegas, running a casino as a front to shelter the warlocks of her town. When did she return to Europe?"

"A few weeks ago, because she wanted to meet me", grinned Percy. "Because Nico's been gushing about me so much that she _had_ to meet me. She's pretty badass."

"Who is this Bianca?", asked Jace curiously, looking between his boyfriend and his best friend.

"Bianca is Nico's older half-sister", supplied Magnus thoughtfully. "Yes, their mother ended up with the same Prince of Hell _twice_. She's very powerful, but passed on the chance of becoming High Warlock of Venice. She's close friends with Catarina."

"Oh. So Annabeth now chose her own warlock to fall for?", smirked Jace mischievously.

"Been teasing her about it _for weeks_ now", grinned Percy pleased. "And I suggested that the ball would be the _perfect_ opportunity to seduce Bianca. After all, behind a mask, she might just find the bravery to try her luck. So, she needs Isabelle to help her pick out a really hot dress."

"What ball?", inquired Magnus with a frown.

"That's the reason he gave _me_ as to why they're here", supplied Jace while tilting his head enough to kiss Magnus just below the earlobe. "Nico is throwing a Halloween ball. A Venetian mask ball. And he invited us. I wanna go to a fancy mask ball. Imagine Alec in a well-cut, old-fashioned suit."

"Mh... I get free food, a party someone else has to throw and I get to dress my precious Shadowhunters up? How could I possibly say no to that?", chuckled Magnus with dark eyes.

"Pe—erfect. So we just wait for the girls to get back and then we portal home", hummed Percy.

"Ah, is the stray kitten that eager to get back to his master?", drawled Magnus.

"Me—eow", replied Percy with a broad smirk.

/break\

Alec thoroughly enjoyed Annabeth's company. She was a nice change of pace from all the Jace and Simon and Clary around him. So much excitement and drama and recklessness. But sadly Annabeth hadn't been too focused while they went through the journals – the journals that gave him nightmares about all the cruel things Valentine had done to _Alec's Jace_.

"Relax, Alec", sighed Lydia gently as he rested her hands on his shoulders. "I told you that _you_ should stay away from those books. I told you I could go through them. You don't have to read about the horrors your parabatai has gone through..."

Alec heaved a sigh and relaxed back against his best friend. "Thanks, Lyd. I know, but..."

He trailed off and shook his head. Lydia raised one elegant eyebrow and motioned for him to follow her. Without questioning, he did so. When they reached the main room, he was pleased to see Magnus stand there. With a smile did Alec instantly gravitate into Magnus' personal space to gently kiss his warlock. It was just a very brief and chaste touch of lips – he didn't feel comfortable with more, but he would not be denied _that_. Magnus smiled against his lips and wrapped one arm around Alec's waist. If Magnus was here, then that meant Jace should be close by too though. Generally, Magnus mostly only showed up at the Institute to pick them up for dates – otherwise, he tried to steer clear ever since the war had ended. Alec couldn't hold it against him.

"Where's Jace?", asked Alec lowly, taking Magnus' hand to link fingers.

"Ah. Our puppy went to chase the kitten around for a bit. Maybe that will exhaust them so they aren't that excited anymore", chuckled Magnus mischievously.

"I really don't like the influence Percy Jackson has on Jace", glowered Alec.

"You're _still_ jealous whenever the two are alone", teased Lydia amused.

Alec continued glowering, making both Magnus and Lydia laugh softly. Together, the three of them headed toward the training-room where Percy and Jace were indeed throwing each other around, attacking with whatever weapon they could reach. The two did make for an intense match-up and Alec always appreciated seeing Jace concentrated and training. But still.

"So, did Jackson say why they're here?", asked Alec softly. "Just a curiosity visit or more?"

"...Didn't you and Annabeth talk at all?", inquired Magnus amused.

The warlock wrapped one arm around Alec's waist as the two of them watched their blonde. "Not about that. She was instantly enthralled by the books, trying to dissect the experiments. And then, when Isabelle came to say hi... she just... grabbed Isabelle and ran out?"

"Ah. So that's where my girlfriend went", chuckled Lydia.

"He—ey. Tall, dark and handsome", purred Percy, suddenly popping up right in front of Alec.

"Jackson", drawled Alec unimpressed.

"He's still pouty about me flirting with you, isn't he, Jace?", asked Percy curiously.

"With me, with his sister, with his best friend, with his warlock", listed Jace patiently.

Percy grinned like a shark and looked from Jace to Lydia and to Magnus. "It's not my fault literally everyone at this Institute is absolutely gorgeous. Seriously, you could use a model-agency as a mundie-cover-up, it's ridiculous. So, I take it the girls are still shopping?"

"Shopping?", echoed Alec and blinked a couple of times.

"Yes! We're invited to the Halloween ball of the High Warlock of Venice", stated Magnus excited. "Which is why we're here. I wanted to pick you up and go shopping with you and Jace, but... now our pretty puppy is all sweaty and sticky. That won't do."

"Oh my", gasped Percy dramatically. "Perhaps you two need to go on ahead alone then while Jace and I shower. I'm sure I'll find the perfect costume for him, no worries."

There was a sly smirk on Percy's lips and Alec scowled a little. "...Your scheming scares me."

"Oh no, I _promise_ you'll love it", assured Percy with a wink, grabbing Jace by the arm.

"Am _I_ going to love it?", asked Jace doubtfully.

"The theme are the roaring 20s, by the way!", called Percy before pausing. "...The seventeen-twenties, that is. Because my boyfriend can't do anything the normal way."

/break\

Annabeth looked absolutely stunning in her golden-white dress, decorated with golden-powdered owl-feathers to compliment the white owl-mask she was wearing. Golden swirls and patterns decorated the mask and a few owl-feathers disappeared into her hair. She looked gorgeous.

"And you're sure Bianca is not going to recognize me?", asked Annabeth with a frown.

Isabelle smiled amused where she was adding the last touch to Annabeth's hair, while Percy snorted. "Dude. You've only been wearing jeans and shirts and 'practical' clothes ever since she met you and your hair is like in a constant bun so it's outta the way. Right now you look like a princess. There's no way she'll recognize you, heck, I barely recognize you."

"You don't look too shabby yourself, Jackson", chuckled Annabeth.

Percy grinned sharply. Yes, he really did look awesome in the fancy, old-fashioned dark-blue suit with the azure-blue frilly dress-shirt beneath. And of course, his mask was _perfect_. He had ordered them a month ago already, for himself and Jace. Speaking of... he still had to lure a puppy out on the dancefloor. Jace was _not_ a fan of this overall idea so far and Percy had some convincing to do with his best friend. A broad smile stretched over his lips. Honestly, when Percy and Annabeth had been send to New York months ago to help during the war, he had not expected to actually made friends, much less such a good friend as Jace. Well, he also hadn't expected to fall in love with the High Warlock of Venice, who oh-so happened to be visiting the High Warlock of Brooklyn.

"Ja—ace. Come on out", drawled Percy, knocking on the door to the bathroom. "Come on."

"No. Fuck you, Jackson. This is embarrassing", grunted Jace irritated.

Percy grinned like a maniac, more than pleased with himself.

/break\

Alec was very content making out with Magnus in the corner. He hated dressing up like that, being all fancy. But Magnus loved dressing them up and Alec loved seeing Magnus so happy and pleased. Not to mention that dark spark in Magnus' eyes when he thought Alec looked particularly stunning. Like right now, which was why they were sitting on a fancy old-fashioned couch in the corner, on a slightly higher platoon. The host and his sister were with them, talking softly to themselves.

Honestly, Nico and Bianca di Angelo looked more like a king and queen than like warlocks as they sat upon their throne-like armchairs, overlooking the grand ball. It all had a bit of a fairy tale charm.

"Where is my Percy?", asked Nico pointedly, glaring at Magnus and Alec.

The two of them parted, Alec sighing frustrated as Magnus turned toward his fellow High Warlock. "Why do you ask me? My focus is on all of this and I doubt Alec's hiding him in his pocket."

Alec flushed as Magnus motioned at him at 'all of this'. Nico huffed and glared at them.

" _Your_ blonde stole my Percy", grunted Nico unimpressed. "Honestly, I'm grateful that I met Percy through you, but whenever your puppy is anywhere close by, I lose Percy's attention."

"Yeah well, I could say the same about 'your kitten'", grunted Alec back.

"Men", sighed Bianca exhausted and shook her head at them, her tight curls bouncing at the motion. "Where is Annabeth? I need just one person who can hold a decent conversation."

"You're just pouty that you don't have someone clinging onto you", pointed Nico out. "Like Annabeth. Oh, don't give me that look. I can't count the times I had to repeat myself because you got lost in Annabeth's cleavage. At least _I_ only get lost in Percy's eyes."

Bianca flushed and glared, while Alec smiled a little to himself. Somehow, Bianca and Nico reminded him of himself and Isabelle. Speaking of, he finally spotted her. She looked like a Disney princess in her dress, with Lydia hanging off one of her arms and Annabeth clinging onto the other. Bianca straightened as she spotted the trio, her focus on the blonde in the owl-mask.

"He—ey. I'm Izzy, Alec's sister", introduced Isabelle herself with a smile. "My girlfriend Lydia. And this one right here would _love_ to dance with you."

She essentially pushed Annabeth into Bianca's arms. The warlock barely had a chance to catch Annabeth, both girls staring into each other's eyes behind the masks for a long moment. Alec rolled his eyes. Honestly, Annabeth really didn't have to worry about a thing there.

"I'd love to dance", smiled Bianca charmingly and led Annabeth out to the dance-floor.

"I'd love to dance too", called Nico out with a grumpy glare.

"...With Annabeth? Not with her parabatai?", asked Isabelle confused as she and Lydia sat down.

"Obviously. But I have no idea where my... oh. Padre mio", whispered Nico stunned.

Alec turned toward where Nico was staring. He grabbed Magnus' arm and tugged hard. At first, Magnus wanted to complain about him crinkling the expensive suit, but then Magnus came to see what Nico and Alec were staring at. Jace and Percy had just entered the room – it was undeniably them. Jace was wearing a beautiful, perfectly cut white suit with golden embroidery – and to top it off, a golden-white Venetian-style mask in the shape of a puppy's face. Next to him Percy was wearing a matching suit in blue and silver, topped off with a silver-blue kitten-face mask.

"Worth the wait?", asked Lydia amused as the two boys approached them.

"Dance with me, High Warlock", ordered Percy as he offered Nico his hand.

Nico was out of his seat in a second, wrapping his arms tightly around Percy's waist and leading him to the dance-floor where he whirled his Shadowhunter around as though they were feathers in the wind. Alec did not have half the mind to think about dancing. He just grabbed Jace around the waist and pulled him down into his lap to kiss him slowly. Their masks were in the way and it was a little awkward, but fuck Alec really needed to kiss his gorgeous parabatai. He ran his fingers through the loose, golden locks of his lover, pulling him closer.

"We are definitely going to keep that mask", whispered Alec breathlessly.

Jace grinned broadly and leaned over to also kiss Magnus, who gladly deepened the kiss and pulled Jace closer. When they parted, they settled down together and looked over to watch Bianca and Annabeth dance, as well as Percy and Nico. Isabelle giggled and grabbed Lydia's hand to pull her along to the dance-floor to join the others. It was nice, seeing their friends happy like this.

"I still think it sucks that we didn't go trick or treating with Clary, Simon, Maia and Bat. I had a dozen different pranks planned to make the vamp piss his pants", huffed Jace.

"I promise you, you can prank Simon as much as you want once we get back. For this weekend, we're just going to enjoy Venice", chuckled Magnus with dark eyes, playing with the hair at the base of Jace's neck. "Now, which one of my pretty Shadowhunters will dance with me first?"

"Him", stated Alec and Jace at the same time, both not liking classic dances.

"Hopeless", sighed Magnus exasperated and got up to walk over to Nico and Percy. "May I?"

Percy smiled and went to take the offered hand, only to have Magnus evade him and look at Nico intensely. The Italian raised one eyebrow, but allowed Magnus to lead the dance while Percy went to join Alec and Jace on the couch. Nico seized Magnus up curiously.

"What do you need, Magnus?", asked Nico gently. "You've been eyeing me all night."

"I could need your help, necromancer", whispered Magnus back. "My pretty blonde recently... died. And was brought back from the dead with the wish from the Angel."

"Brought back from the dead?", grunted Nico surprised and stared at Jace from over Magnus' shoulder. "...Interesting. And the wish from an Angel, you say?"

"Yes. His sister raised the Angel and wished Jace back to life", sighed Magnus.

"And what do you need me for?", inquired Nico.

"I know you've always been very fascinated by necromancy. You're the number one expert on it. And... something went _wrong_ , of course it did", sighed Magnus lowly. "Jace, he's had... pain-attacks. Nightmares. Hallucinations. I've already consulted every book I have, but... I know you're more well-versed in the dark magic of bringing people back to life. I had hoped..."

"I'll look at him", assured Nico softly, eyes fixed on Jace and Percy fooling around on the couch, with an exasperated Alec next to them. "Bianca might be able to help too. I'll consult my books tonight, you bring your pretty blonde to me in the morning so he can tell me in his words."

"Thank you, Niccoló", whispered Magnus relieved.

"Don't be an idiot, Bane", grunted Nico. "Any time. And you should know that."

"I really do hope the two of you are done with whatever secret conversation you had, because as much as I hate dancing, hand me my boyfriend, Nico", interrupted Alec.

Magnus chuckled as he gladly pulled Alec close while Nico left to head back to Percy. Percy was by now busy making fun of Annabeth and Bianca, together with Lydia, Isabelle and Jace. Apparently, Annabeth had realized that Bianca had recognized her and the two women had _finally_ figured things out. Nico heaved a relieved breath. If he had to endure his sister mooning over Percy's parabatai any longer, he was going to shoot himself. Smiling, he sat down between Bianca and Percy, pulling his kitten up into his lap. Percy purred pleased and snuggled up to him, stealing a kiss.

"I love your costume, gattino", whispered Nico lowly. "My gorgeous little kitten."

"Meow", grinned Percy mischievously. "Happy Halloween, my big bad warlock."

"Urgh. So sappy. Makes me want to puke", groaned Jace, making gagging noises.

Honestly, Nico cherished the friendship between Percy and Jace. The two of them shared a special bond and it was endearing to see them train, quarrel, banter and drown others in sarcasm. It was the main reason Nico had decided to host this large ball this year – so Percy could invite their New York friends. Well, them and everyone else they knew. Thankfully, Nico's mansion had a big enough ball-room. Nico frowned as Percy climbed off his lap.

"Where are you going?", huffed Nico, grabbing the air where Percy had previously been.

"Da—ancing", chimed Percy and grabbed Jace's hand.

"What? No! Jackson, no", growled Jace defensively.

"Jace, _yes_ ", smirked Percy. "Come on. Let's tease our boyfriends a little bit."

"...You're an awful person", snorted Jace and shook his head. "I like that in you."

Percy grinned slyly and moments later, the two of them were essentially rubbing against each other on the dance-floor. It was a lot like the two of them when training. Fluent, elegant, graceful, intriguing. Too hot to be allowed. And this right now; also too obscene to be seen in public.

"Puppy, I think you've been playing with the kitten for long enough now", declared Magnus after about five minutes, grasping Jace around the waist and pulling him away from Percy. "Pay attention to Alexander and me. Upstairs. In our room. I've had enough of Halloween. I want to get my pretty Shadowhunters out of their costumes for the night. ...The masks can stay on."

Jace grinned broadly as he allowed himself to be dragged out of the hall, Alec gladly stumbling after them. Percy laughed softly as he watched them before he headed back to his own warlock. With a pleased grin on his lips, he let himself fall down onto Nico's lap.

"So, you gonna fix Jace tomorrow, right?", whispered Percy softly.

"...How do you...", started Nico surprised, wrapping his arms around Percy's waist.

"Jace told me about the pains. About what happened. I know what you do. I mainly wanted this big Halloween ball to have an excuse to have those three over here for a weekend", replied Percy.

Nico chuckled softly and placed a kiss beneath Percy's earlobe. His brilliant little Shadowhunter always looked out for those he care for. It was one of the things he loved most about Percy.

 _~*~ The End ~*~_

* * *

 _Author's note: I wanted to write a Halloween fic. But I couldn't decide if I wanted to write for Nicercy or for Malace. So I decided to do both. And this crossover world that I created is fun to write for, so I figured - why not explore it some more._

 _And no worries, this isn't the last one set in this world either. So, no complaints about how this didn't deal with Jace's pains. This is just supposed to be a sweet, short Halloween thing - that also had to be, ya know, finished by Halloween so there's that. The next one however will deal with how Bianca and Nico help fix Jace. ;)_


End file.
